Simtk.org has become a hub for the dissemination of tools related to physics-based simulation in biomedical research, with more than 380 projects and 8000 users. Our future plans are driven by this rapid growth in the number of users of simtk.org, and the feedback we receive from them. Over the next four years, we will build the capabilities of simtk.org to create a sustainable model for support for its many users. Our plan for improved support is based on social networking for peer-support and virtual machines for replication of research results. The rapid expansion of social networks, such as Facebook, is an important development since the NCBC program began in 2004. Some of our software applications have a critical mass of users who want to interact and support one another. Thus, we plan to implement tools based on social networking paradigms to enable peer support. The development of virtual machines provides an opportunity for users of simtk.org to reproduce the results of others. Virtual machines provide a mechanism for an operating system, executable codes, and data sets to be pre-loaded into a binary format that represents an "image" of a fully functional machine. Our pilot studies have demonstrated the ability to deliver binaries, documentation, models and full simulation trajectories. Thus, going forward, we will improve the ability of simulation scientists to share their work in full detail.